this.$nextTick(() => {
 	this.$refs.side_menu.updateOpened()
  	this.$refs.side_menu.updateActiveName()
  });

<template>
 <div class="leftNav">
 <Menu ref="side_menu" theme="dark" accordion v-for="(menuItem, menuIndex) in menuList" :key="menuIndex" :active-name="$route.name">
 
  <!-- 展开没有子菜单 -->
  <MenuItem v-if="!menuItem.children || menuItem.children.length==0" :key="menuIndex" :name="menuItem.to" :to="menuItem.to">
  <Icon :type="menuItem.icon" />
  <span>{{ menuItem.name }}</span>
  </MenuItem>
 
  <!-- 展开有子菜单 -->
  <Submenu v-else :name="menuIndex">
   <template slot="title">
    <Icon :type="menuItem.icon" />
    <span>{{menuItem.name}}</span>
   </template>
   <MenuItem v-for="(item, index) in menuItem.children" :key="index" :name="item.to" :to="item.to">{{item.name}}</MenuItem>
  </Submenu>
 </Menu>
 </div> 
   
</template>
<script>
export default {
 data() {
 return {
  menuList: [
  {
   name: "首页",
   to: "home",
   icon: "ios-archive-outline"
  },
  {
   name: "关于",
   to: "about",
   icon: "ios-create-outline"
  },
  {
   name: "菜单分类1",
   icon: "md-person",
   children: [
   {
    name: "用户",
    to: "user"
   }
   ]
  },
  {
   name: "菜单分类2",
   icon: "ios-copy",
   children: [
   {
    name: "测试",
    to: "test"
   }
   ]
  }
  ]
 };
 },
 created() {
 // 数据我先写静态的，可在初始化的时候通过请求，将数据指向menuList。
 // ajax成功回调后 this.menuList = response.data;
 // 别忘记更新菜单
 // this.$nextTick(() => {
 //	this.$refs.side_menu.updateOpened()
 //	this.$refs.side_menu.updateActiveName()
 //});
 }
};
</script>
<style lang="scss" scoped>
/deep/
 .ivu-menu-dark.ivu-menu-vertical
 .ivu-menu-item-active:not(.ivu-menu-submenu) {
 border-right: none;
 color: #fff;
 background: #2d8cf0 !important;
}
</style>